6 Steel; aluminium and its alloys; aluminium ingots; ingots of common metal; rings of metal; metal construction materials; common metals and their alloys; metal hardware; metal forgings; steel forgings; rolled steel; metal mouldings; hot-rolled steel bars; steel buildings; water-pipe valves of metal; valves of metal, other than parts of machines; cast steel; steel, unwrought or semi-wrought; laminated metals; structural steels